PI illustration display device



Within a transparent rectangle, balls illustrating the length of the circumference of a circle travel in hollow tubular channel.

FIG. 1 is an isometric view of the PI illustration display device.

FIG. 2 is a front view of the PI illustration display device.

FIG. 3 is a side view of the PI illustration display device; and,

FIG. 4 is a top view of the PI illustration display device. 

The ornamental design for a PI illustration display device, as shown. 